Unloader valve



Feb. 20, 1951 c. M. oLr-:ARY

UNLOADER VALVE Original Filed July 10, 1944 atented Feb. 20, 1951 UNETEDSTATES PATENT OFFICE Original application July 10, 1944, Serial No.544,209, now Patent No. 2,423,111, dated July 1,

1947, Serial No. 742,382

4 Claims. (Cl. 137-41153) The present invention relates to an apparatusfor causing outflow ci well uid from wells of low productivity index,and is a division of applicants copending application, Serial No.544,299, filed July 1G, 1944, now Patent No. 2,423,111, granted July 1,1947.

It is the general object of the present inven-` tion to provide animproved form of blow-ofi valve for use in bottom hole gas-operated oilwell pumps to aerate the column of oil when its density exceeds adesired maximum in value.

Another object of the invention is to provide an improved combination ofbottom hole gas-- operated pump with a blow-off valve of the typementioned associated with the operating gas supply of the pump.

Other objects, which will become apparent from the followingspecification and accompanying drawing, include the provision of anapparatus of the type mentioned which may be readily lowered into theoutiiow tubing of a well on the gas tubing and which is simple andrugged in design and construction.

The invention is fully disclosed by way of example in the followingdescription and in the accompanying drawing, in which:

Figure 1 is a vertical section of the device, at the beginning of thesuction stroke;

Figure 2 is a similar section, showing the posi'.A tion of parts at thebeginning of the pressure stroke; and

Figure 3 is a section on the line 3 3 of Figure 2.

In Figure l is shown the well outflow tubing 3, which extendssubstantially to the bottom of the well bore within the usual wellCasing, not shown. n the bottom of the tubing 3 is iitted an endpiece 4formed with a seat 4. Within the tubing 3, in turn, is mounted the powergas tubing or pressure flow tube 5', to the lower end of which is fixedan enlarged tube 5 carrying a pumping mechanism designated generally bythe numeral l.

In the tube 5 is mounted a block 'I having mounted in its upper end astrainer or Scale trap il communicating with a central passage formed inthe block. To the block 1 is secured a downwardly extending sleeve Iilformed with a series of ports I2 for a purpose that will pres ently bedescribed. Beneath the ports, a crossover Iff is attached to the sleeveIll and is ,formed with an axial passage It, for a purpose that willpresently appear. Over the passage and within the sleeve le is mountedan unloader valve I3 having a head 2t adapted to seat ona seat 2l at theupper end of the passage I6. `The valve Divided and this applicationApril 18,

I8 is formed with an axial passage 22,y and is suspended from the block'I by a bellows 24 com-v municating with the passage 9. Another bellows2E also joins the members l and I8 and forms an annular chamber 28around the bellows 24, which chamber is sealed at substantiallyatmospheric pressure. When the unloader valve is seated, the bodythereof forms a space 29 above the crossover I4 and in communicationwith the ports I2.

A jacket or extension tube 30 is suspended from the crossoverV I4 and isalso spaced from the tubing 3 to form a continuation of the annularchamber 6 between tube 3 and the aligned tubes 5, I and 3B. The lowerend oi the crossover is formed as a motor piston cylinder head 32, fromwhich is suspended a motor piston cylinder 34 spaced annularly at Stfrom the jacket 30. Between the crossover I4 and the head 32 is formed anumber of radial ports 38 communicating with the axial passage I6.

In the cylinder 34 is slidably mounted a motor piston including acylindrical sleeve 40 formed at its upper end with a skirt 42 ofsomewhat larger internal diameter. The juncture of the two diametersforms a valve seat 44. At the lower end of the motor piston is formed ahead 46, and near the head are ports 48 forming a passage to theinterior of the piston. The head 46 is formed with an axial bore 50which has its upper end enlarged at 52 for a purpose that will presentlybe described. A pump plunger rod 54 passes through the bore Sil withslight clearance therein, and carries at its upper end a motor pistonvalve head 56 adapted to close on the seat 44.

A spring 58 is inserted between the valve head and the lower piston head46 and holds the valve head 56 open under certain conditions that willpresently be described. The rod 54 is formed with a collar 6D having asliding rit in the enlarged bore 52.

On the lower end of the extension 3u is secured a downwardly extending`barrel 62 of smaller diameter and joined to the extension by an annulardisk connector 64. The lower end or barrel 62 carries a tting 63inserted in. the seat 4.

The lower end of the pump plunger rod 54 carries a pump plunger 66working in barrel t2. The area of the plunger 66 is smaller than thearea of the seat 44. Pump rod 54 is provided with stop collar 61, whichlimits the separation of the valve 5S and piston 4t in the open positionof the valve.

The power gas flows through the space 6B be- Y valve 56 comes to rest onseat 45.

tween the connector 65. and the lower end of the motor piston cylinder34. While the disk connector acts as a lower stop for piston 45, contactbetween the piston and disk 54 does not block communication betweenspace 69 and the pump barrel 62.

In the lower surface of the cylinder head 52 is mounted an upwardlyopening check valve, including a ball 1E) adapted to close on a seat s.The valve communicates through a restricted lateralpassage l2 in thecrossover is with the space 6. The passageway l2 does not communicatewith the ports 38.

In the lower end of the pump barrel 62 is mounted a discharge valvehousing lprovided in its lower end with a seat 18. rihe housing i6contains a ball valve S adapted to close downwardly in the seat i8, andis formed with a suitable number or" laterally extending ports 82registering wtih ports 85m the barrel through connecting nipples 84,thereby bringing the valve housing into communication with the lower end5 of the well uid space. The pump chamber S5 between the housingl andpump plunger 56 is in communication with the space within barrel 62 andbelow housing l5 through the passages between the nipples 64, as bestshown in Figure 3.

A iluid intake pipe 96 from the well is inserted with the tting,constitutes the standing valvev or intakevalve assembly.

In Figure 2, the parts are illustrated in the position they assume atthe beginning of the pumping or downward stroke of plunger S6. The powergas iiows down tubing 5 through the, trap 8, bellows 24, passages 22 andi5, ports spaces and 69, ports 48 and the open valve seat t4 into thechamber 94 above the valve head 56. chamber 94 communicates through the,restricted passage 'i2 with the space which. is at a pressure determinedby the head of well fluid standing therein and less than the power gaspressure. However, due to the restricted passageway l2, the pressure inchamber 54 may be substantially equal to the pressure of the power gassupply. This same pressure acts on both sides oi valve 56, both sides ofpiston 4i), and also on the top of plunger 66. sures on the piston lill,itself, are balanced, and

the power gas moves the plunger 55 downwardly through its pumping strokeby reason of the fact that it is acting on an excess upwardly-facingarea on the plunger and valve unit 55 and 5S equal to thecross-sectional area of plunger 66. During the pumping stroke, thatportion of the power gas which ows through passage 'i2 enters the columnof oil in tube t and provides a gas lift effect. During the pumpingstroke, Spring 53 holds the valve 55 open by moving the then balancedpiston 45 downwardly in advance of the valve. However, near the end ofthe pumping stroke, piston 45 engages disk 5ft and is brought to a stop.Thereupon continued downward movement of plunger 56 compresses spring 5Sand The valve 55 is now held on its seat by the pressure above the motorpiston 45 and the power gas pressure acting on plunger 65. When thevalve 56 is seated, the pressure effective area of the upper side of thevalve is greater than the pressure effective area of its lower side bythe cross-sectional area The,

During this condition, therefore, the pres-4 CII of the plunger 65.which is attached to valve rod 66. y

The downward pressure in chamber 94 is now diminishing through therestricted exhaust pas sage l2, while the upward gas pressure at thespace 59 remains constant against the lower end of motorpiston 45. Thepressure effective area of the lower side of motor piston lid, which issubject to power gas pressure, is its area minus the area ofpump plunger66. When the pressure in chamber 9s above the motor piston 45 drops to apoint where the pressure gas on the lower side of piston 46 exerts aforce greater than the force on its upper side, the piston valve 53, rod6) and plunger 6i? move upward. The suction stroke of the plunger isthus initiated, raising the valve Si.' and seating the valve 8s bysuction in the chamber S5, as shown in Figure l, drawing which it isexhausting. The size of the opening' 'i2 and the relative diameters ofpistonifii, valve 56 and plunger 56 are so chosen for any given powergas pressure and well iluid pressure that valve 5S remains closed duringthe suction stroke until the skirt 4Z of piston 40 strikes the cylinderhead 32.

When the extended skirt 42 strikes the head 32 at the end of its suctionstroke, the pressure in chamber 94 further reduces until the tension ofspring 58 and the pressure responsive area on the underside of seatedValve 56 are suilcient to open the valve against its` upper pressurearea, as shown in Figure 2. There is now equal unit pressure on bothsides of the motor piston 46 and the pressure gas now exerts a resultantdownward force against the area of plunger 66 to I initiate thedownstroke, as previously described. The opening of valve 55 in relationto seat 44 is limited by stop collar 6l.

Once the valve 56 is seated, it cannot come oli"V valve 92 is seated andvalve 86 is unseatedbypressure in the chamber 86, as shown in Figure 2.The wellv fluid that was previously drawnV into barrel 62 is nowdischarged into the f space 6', 6.

It is obvious that there is exhaust of power gas on the power stroke, sothat the flow of gas into the head of well fluid is continuous. Thisflow of gas is ordinarily sufficient to .produce a constantly flowingdischarge of aerated well uid to the surface of the ground.

Back ow of well fluid into the chamber 94 is prevented by the inwardlyclosing check valve 16 on its seat 'I0'.

In the event that the head of well fluid becomes,

too dense for continuous aerated discharge, the unloader valve I8provides means for a blow-oli. This' is brought about by well fluidpressure being built up in the outflow tubing and reacting against thearea of the unloader valve I8 eX- posed to well iuid at the space 29.The unloader valve I8 is normally held seated by pres'- sure'gas actingon4 that portion of valve I8 confined by bellows 24, this area beingsubstantially larger than the seated area of valve I8 on its seat 2l.The passage 22 through valve I8 is smaller in cross-sectional area thanthe area of valve seat 2|. This provides a continuous pressure on thevalve I8, tending to hold it upon its seat 2|.

When the unloader valve I8 is raised and the gas pressure iscommunicated to the head of well iiuid at the ports I2, the friction ofthe flowing fluid in chamber ii imposes a greater pressure in space 29and on the valve I8 than at the time the valve was rst unseated. Thisadditional force insures that the valve I8 will remain open until suchtime as the well fluid starts to discharge at the surface. The backpressure of the discharging fluid eventually drops to a point where thepressure in bellows 24 is suiiicient to seat the valve. The fluidremaining in tubing 3 continues to discharge by the expansion of thepower gas trapped inthe tubing by the seating of valve I8. The quickaction of the valve thus saves pressure gas and permits the pumpingmechanism to commence operation without waiting for a complete blow-downof the well. A balanced pressure condition, holding the pumpinoperative, would be of only momentary duration.

Thus, it is not necessary with this unloader valve to blow the tubingdry in order to close the valve. The result of this characteristic is avery positive and economical operation.

It is preferable that the well fluid pressure responsive parts of valvei8 be of a larger area than the power gas pressure responsive partstending to hold the valve upon its seat 2l,

whereby to permit the opening of Valve I8 by low well fluid heads.

It will be noted that the cross-sectional area of passage 22 is smallerthan the area of bellows 24. When the valve I8 is away from its seat 2I,the pressure in the area coniined by bellows 24 and flowing through therestricted passage 22 urges the valve on its seat, It is this force thatmoves the valve toward its seat when a portion of the well fluid hasbeen ejected at the surface and permits operation of the `pumpingmechanism, as previously set forth.

The higher the pressure in the system, the greater the slug or head ofwell iiuid must be to overcome the greater force exerted on the gaspressure responsive parts. If the pressure be lowered, a correspondinglysmaller head will be required to open the unloader valve. A denitediierential can be established between all the parts or the pumpingmechanism and the unloader valve to be applicable over a wide range ofvarying well conditions by control of the power gas pressure.

The parts of the unloading valve are so proportioned that when thecolumn of fluid loads up to a predetermined pressure where theperformance of the pumping mechanism is retarded, the valve opens andthe power gas ejects the fluid from the tubing. Such loading up of thetubing is sometimes brought about by a slug of Water or by a drop in gaspressure at its source 6. or by the cutting in of other wells on. thesaine line, which will also reduce the gas pressure.

By regulation of input gas pressure, the head of well uid necessary toopen the blow-olf` valve I8 can be controlled. The relation of therespective pressure responsive areas to each other can be so designed tooperate under varied well conditions, and, by regulation of the gaspressure, can be made to pump deep or shallow wells with a minimum ofgas.

It is understood that various areas of motor pistons, valves, pumpplungers and various spring tensions and sizes of Vents may be used tomeet various well conditions.

The disclosed pumping mechanism can be of the insert type removable withthe power gas string, as illustrated, or of the tubing type requiringremoval of both strings to service the pump. The pump can be so arrangedto produce the well fluid through the smaller string of pipe, in whichcase the outer string of pipe would be used to conduct power gas to thepumping mechanism.

Although a specific embodiment of the invention has been illustrated anddescribed, it will be understood that various alterations in the detailsof construction may be made without departing from the scope of theinvention as indicated by the appended claims.

What is claimed is:

l. An unloader valve comprising a supporting member having an inlet porttherein, an expansible elastic bellows, which is generally circularincross section, secured in sealed relation at one end to saidsupporting member in position to receive and conduct fluid entering saidport, a Valve member secured in sealed relation to the opposite end ofsaid bellows and having an opening therethrough of smaller diameter thanthe diameter of said bellws and communicating with the interior of thebellows, a third member mounted in fixed position with respect to thesupporting member and having an outlet port in alignment with theopening in said valve member, cri-operating valve seating areas on thevalve member and third member surrounding the opening and outlet portrespectively and adapted to be forced into seating engagement bypressure within the bellows acting on the valve member, and a secondbellows of larger diameter and surrounding the first bellows and securedin sealed relation at its opposite ends to the supporting member andvalve member respectively, said second bellows and said supportingmember being of larger diameter than said valve seating areas wherebyfor any given fluid pressure eX isting within the inner bellows saidvalve member will be unseated by a predetermined pressure existing inthe space surrounding the second bellows.

2. A valve for automatically aerating a column of liquid in a welloutflow tubing, comprising a housing having a gas supply passageway, anoutlet port in said housing, a movable valve element having a restrictedopening therethrough in constant communication with said passageway, astationary valve seat adapted when engaged with said valve to preventflow through said opening to said port, and means responsive to thepressure at said port tending to lift said valve from said seat.

3. A valve for automatically aerating a column of liquid in a welloutflow tubing, comprising a housing having a gas supply port, an outletport in sad'housing, a gas ow passage adapted to connect said ports, avalve for controlling flow through said passage, a movable pressureresponsive means Subject to the pressure at said outlet port for openingsaid Yvalve when the pressure at said outlet port reaches apredetermined value, Yand means responsive to the pressure differentialacross said valve due to the gas flow through said passage for exertingan opy posing force tending to close the valve.

4. A gas supply and unloader valve mechanism for a gas-operated bottomholewell pump having an operating gas supply conduit and a liquiddischarge conduit, said valve comprising a chamber having three ports,one of said ports being a discharge port, the second being a gas supplyport and the third being a pump supply outlet port, a-movable valveelement in said chamber and adapted to engage the third port,

said element having a restricted opening therethrough adapted to delivergas from the second port through said third port when the valve elementis in engagement with the third port, and means to prevent flow of gasfrom the second port to the third port except through -said restrictedopening, said last means being movable and subject to the pressure atthe rst port Vacting in a direction to lift the Vvalve element off thethird port and thereby place said restricted opening in communicationwith the rst -port and also subject when the valve engages said thirdport to a force incident to the pressure drop through said restrictedopening tending to hold the valve in engagement with said third port.

Y CHARLES M. OLEARY.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,543,488 Todd June 23, 19252,029,457 Beardmore Feb. 4, 1936 2,254,631 Temple Sept. 2, 19412,269,189 Downs Jan. 6, 1942 2,312,201 Thompson et al. Feb. 23, 19432,328,841 OLeary Sept. '7, 1943 2,342,855 Green Feb. 29, 1944 2,356,423OLeary Aug. 22, 1944 2,368,999 OLeary Feb. 6, 1945 2,423,111 OLeary July11, 1947

